Tools or bits have historically been selectably removably retained in tool holders, base blocks, and the like. When they are worn out, they may be driven from their mountings and replaced by new or reconditioned such tools. Such a tool with a hardened tip can be found in applicant's prior U.S. Pat. No. 6,739,327. For some time, such cutting tools have had hardened tips, preferably made of tungsten carbide.
More recently, the use of diamond material, either industrial or manmade, as coatings or layers on the tips of the inserts, preferably still made of tungsten carbide, have found their way into material removing equipment. Tungsten carbide tipped tools have generally been rotatable in their bit holders or base blocks. The use of longer lasting diamond tipped inserts has for some operations given way to a one piece tool-bit holder combination, sometimes called a pick. With such a pick, the diamond tipped insert is integrally formed at the top of the bit holder which, in turn, is selectably removeably mounted in a base block.
The additional working life of the diamond tipped inserts has meant that generally longer use life could be had without needing rotatability of the tools. However, at present, the layering or coating of such diamond material on insert bases has proven not to be usable in all such material removing instances. While such diamond tipped tools may be usable to remove the top of long stretches of straight highway materials, such diamond tipped tools have not been so successful in removing material from concrete surfaces. This has necessitated changing the entire set of picks (or bit/holder combinations) from a drum when removing portions of certain stretches of highway segments. Aside from changing out the picks on an entire drum, which include potentially hundreds of picks, there also exists the potential of maintaining multiple drums, some having diamond tipped inserts mounted on the drums and others having tungsten carbide tipped inserts mounted on the drums. The added costs in downtime, changing picks, and/or in capital in maintaining multiple drums is substantial.
A need has developed for improved cutting tools or bits, especially diamond tipped cutting tools, that may be more easily and quickly removed and changed out of drums or endless chains utilized for mounting such tools thereon.